This invention relates to a vehicle traction control system and, more particularly, to such a system that includes limiting wheel spin by withholding fuel from selected cylinders of the engine by disabling selected fuel injectors in a port injected internal combustion engine.
Various methods have been proposed for preventing an excessive spinning condition of the driven wheels of a vehicle during vehicle acceleration when the operator initiated engine torque delivered to the vehicle driven wheels are such that the frictional forces between the tire and the road surface are overcome. These methods include the adjustment of engine torque and/or the application of the brakes of the driven wheels when an excessive acceleration spinning condition is detected. One method of adjusting engine torque output for limiting wheel spin during vehicle acceleration controls the individual injectors in a port injected internal combustion engine so as to selectively withhold fuel from selected cylinders. In this form of system, the cylinders to which fuel is withheld intake only air during their intake strokes and do not contribute to the torque output of the engine. The number of cylinders to which fuel is withheld determines the amount of reduction in the engine torque output.
In limiting wheel spin, the number of cylinders disabled through the withholding of fuel is a function of the torque reduction required before there is recovery from the excessive spin condition which in turn is a function of operator input, road surface condition, etc. It is not desireable, however to allow the number of cylinders disabled to limit wheel spin to increase unconstrained. Unlimited disabling of cylinders may result in undesireable traction control system performance and may give rise to elevated temperatures of a catalytic converter typically employed in vehicle exhaust systems.